/* SDSLib 2.0 -- A C dynamic strings library
 *
 * Copyright (c) 2006-2015, Salvatore Sanfilippo <antirez at gmail dot com>
 * Copyright (c) 2015, Oran Agra
 * Copyright (c) 2015, Redis Labs, Inc
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   * Neither the name of Redis nor the names of its contributors may be used
 *     to endorse or promote products derived from this software without
 *     specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>
#include "sds.h"
#include "sdsalloc.h"

static inline int sdsHdrSize(char type)
{
	switch (type & SDS_TYPE_MASK)
	{
	case SDS_TYPE_5:
		return sizeof(struct sdshdr5);
	case SDS_TYPE_8:
		return sizeof(struct sdshdr8);
	case SDS_TYPE_16:
		return sizeof(struct sdshdr16);
	case SDS_TYPE_32:
		return sizeof(struct sdshdr32);
	case SDS_TYPE_64:
		return sizeof(struct sdshdr64);
	}
	return 0;
}

static inline char sdsReqType(size_t string_size)
{
	if (string_size < 32)
		return SDS_TYPE_5;
	if (string_size < 0xff)
		return SDS_TYPE_8;
	if (string_size < 0xffff)
		return SDS_TYPE_16;
	if (string_size < 0xffffffff)
		return SDS_TYPE_32;
	return SDS_TYPE_64;
}

/* Create a new sds string with the content specified by the 'init' pointer
 * and 'initlen'.
 * If NULL is used for 'init' the string is initialized with zero bytes.
 *
 * The string is always null-termined (all the sds strings are, always) so
 * even if you create an sds string with:
 *
 * mystring = sdsnewlen("abc",3);
 *
 * You can print the string with printf() as there is an implicit \0 at the
 * end of the string. However the string is binary safe and can contain
 * \0 characters in the middle, as the length is stored in the sds header. */
sds sdsnewlen(const void *init, size_t initlen)
{
	void *sh;
	sds s;
	char type = sdsReqType(initlen);
	/* Empty strings are usually created in order to append. Use type 8
	 * since type 5 is not good at this. */
	if (type == SDS_TYPE_5 && initlen == 0)
		type = SDS_TYPE_8;
	int hdrlen = sdsHdrSize(type);
	unsigned char *fp; /* flags pointer. */

	sh = s_malloc(hdrlen + initlen + 1);
	if (sh == NULL)
		return NULL;
	if (!init)
		memset(sh, 0, hdrlen + initlen + 1);
	s = (char*) sh + hdrlen;
	fp = ((unsigned char*) s) - 1;
	switch (type)
	{
	case SDS_TYPE_5:
	{
		*fp = type | (initlen << SDS_TYPE_BITS);
		break;
	}
	case SDS_TYPE_8:
	{
		SDS_HDR_VAR(8, s);
		sh->len = initlen;
		sh->alloc = initlen;
		*fp = type;
		break;
	}
	case SDS_TYPE_16:
	{
		SDS_HDR_VAR(16, s);
		sh->len = initlen;
		sh->alloc = initlen;
		*fp = type;
		break;
	}
	case SDS_TYPE_32:
	{
		SDS_HDR_VAR(32, s);
		sh->len = initlen;
		sh->alloc = initlen;
		*fp = type;
		break;
	}
	case SDS_TYPE_64:
	{
		SDS_HDR_VAR(64, s);
		sh->len = initlen;
		sh->alloc = initlen;
		*fp = type;
		break;
	}
	}
	if (initlen && init)
		memcpy(s, init, initlen);
	s[initlen] = '\0';
	return s;
}

/* Create an empty (zero length) sds string. Even in this case the string
 * always has an implicit null term. */
sds sdsempty(void)
{
	return sdsnewlen("", 0);
}

/* Create a new sds string starting from a null terminated C string. */
sds sdsnew(const char *init)
{
	size_t initlen = (init == NULL) ? 0 : strlen(init);
	return sdsnewlen(init, initlen);
}

/* Duplicate an sds string. */
sds sdsdup(const sds s)
{
	return sdsnewlen(s, sdslen(s));
}

/* Free an sds string. No operation is performed if 's' is NULL. */
void sdsfree(sds s)
{
	if (s == NULL)
		return;
	s_free((char*) s - sdsHdrSize(s[-1]));
}

/* Set the sds string length to the length as obtained with strlen(), so
 * considering as content only up to the first null term character.
 *
 * This function is useful when the sds string is hacked manually in some
 * way, like in the following example:
 *
 * s = sdsnew("foobar");
 * s[2] = '\0';
 * sdsupdatelen(s);
 * printf("%d\n", sdslen(s));
 *
 * The output will be "2", but if we comment out the call to sdsupdatelen()
 * the output will be "6" as the string was modified but the logical length
 * remains 6 bytes. */
void sdsupdatelen(sds s)
{
	int reallen = strlen(s);
	sdssetlen(s, reallen);
}

/* Modify an sds string in-place to make it empty (zero length).
 * However all the existing buffer is not discarded but set as free space
 * so that next append operations will not require allocations up to the
 * number of bytes previously available. */
void sdsclear(sds s)
{
	sdssetlen(s, 0);
	s[0] = '\0';
}

/* Enlarge the free space at the end of the sds string so that the caller
 * is sure that after calling this function can overwrite up to addlen
 * bytes after the end of the string, plus one more byte for nul term.
 *
 * Note: this does not change the *length* of the sds string as returned
 * by sdslen(), but only the free buffer space we have. */
sds sdsMakeRoomFor(sds s, size_t addlen)
{
	void *sh, *newsh;
	size_t avail = sdsavail(s);
	size_t len, newlen;
	char type, oldtype = s[-1] & SDS_TYPE_MASK;
	int hdrlen;

	/* Return ASAP if there is enough space left. */
	if (avail >= addlen)
		return s;

	len = sdslen(s);
	sh = (char*) s - sdsHdrSize(oldtype);
	newlen = (len + addlen);
	if (newlen < SDS_MAX_PREALLOC)
		newlen *= 2;
	else
		newlen += SDS_MAX_PREALLOC;

	type = sdsReqType(newlen);

	/* Don't use type 5: the user is appending to the string and type 5 is
	 * not able to remember empty space, so sdsMakeRoomFor() must be called
	 * at every appending operation. */
	if (type == SDS_TYPE_5)
		type = SDS_TYPE_8;

	hdrlen = sdsHdrSize(type);
	if (oldtype == type)
	{
		newsh = s_realloc(sh, hdrlen + newlen + 1);
		if (newsh == NULL)
			return NULL;
		s = (char*) newsh + hdrlen;
	} else
	{
		/* Since the header size changes, need to move the string forward,
		 * and can't use realloc */
		newsh = s_malloc(hdrlen + newlen + 1);
		if (newsh == NULL)
			return NULL;
		memcpy((char*) newsh + hdrlen, s, len + 1);
		s_free(sh);
		s = (char*) newsh + hdrlen;
		s[-1] = type;
		sdssetlen(s, len);
	}
	sdssetalloc(s, newlen);
	return s;
}

/* Reallocate the sds string so that it has no free space at the end. The
 * contained string remains not altered, but next concatenation operations
 * will require a reallocation.
 *
 * After the call, the passed sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdsRemoveFreeSpace(sds s)
{
	void *sh, *newsh;
	char type, oldtype = s[-1] & SDS_TYPE_MASK;
	int hdrlen;
	size_t len = sdslen(s);
	sh = (char*) s - sdsHdrSize(oldtype);

	type = sdsReqType(len);
	hdrlen = sdsHdrSize(type);
	if (oldtype == type)
	{
		newsh = s_realloc(sh, hdrlen + len + 1);
		if (newsh == NULL)
			return NULL;
		s = (char*) newsh + hdrlen;
	} else
	{
		newsh = s_malloc(hdrlen + len + 1);
		if (newsh == NULL)
			return NULL;
		memcpy((char*) newsh + hdrlen, s, len + 1);
		s_free(sh);
		s = (char*) newsh + hdrlen;
		s[-1] = type;
		sdssetlen(s, len);
	}
	sdssetalloc(s, len);
	return s;
}

/* Return the total size of the allocation of the specifed sds string,
 * including:
 * 1) The sds header before the pointer.
 * 2) The string.
 * 3) The free buffer at the end if any.
 * 4) The implicit null term.
 */
size_t sdsAllocSize(sds s)
{
	size_t alloc = sdsalloc(s);
	return sdsHdrSize(s[-1]) + alloc + 1;
}

/* Return the pointer of the actual SDS allocation (normally SDS strings
 * are referenced by the start of the string buffer). */
void *sdsAllocPtr(sds s)
{
	return (void*) (s - sdsHdrSize(s[-1]));
}

/* Increment the sds length and decrements the left free space at the
 * end of the string according to 'incr'. Also set the null term
 * in the new end of the string.
 *
 * This function is used in order to fix the string length after the
 * user calls sdsMakeRoomFor(), writes something after the end of
 * the current string, and finally needs to set the new length.
 *
 * Note: it is possible to use a negative increment in order to
 * right-trim the string.
 *
 * Usage example:
 *
 * Using sdsIncrLen() and sdsMakeRoomFor() it is possible to mount the
 * following schema, to cat bytes coming from the kernel to the end of an
 * sds string without copying into an intermediate buffer:
 *
 * oldlen = sdslen(s);
 * s = sdsMakeRoomFor(s, BUFFER_SIZE);
 * nread = read(fd, s+oldlen, BUFFER_SIZE);
 * ... check for nread <= 0 and handle it ...
 * sdsIncrLen(s, nread);
 */
void sdsIncrLen(sds s, int incr)
{
	unsigned char flags = s[-1];
	size_t len;
	switch (flags & SDS_TYPE_MASK)
	{
	case SDS_TYPE_5:
	{
		unsigned char *fp = ((unsigned char*) s) - 1;
		unsigned char oldlen = SDS_TYPE_5_LEN(flags);
		assert(
				(incr > 0 && oldlen + incr < 32)
						|| (incr < 0 && oldlen >= (unsigned int )(-incr)));
		*fp = SDS_TYPE_5 | ((oldlen + incr) << SDS_TYPE_BITS);
		len = oldlen + incr;
		break;
	}
	case SDS_TYPE_8:
	{
		SDS_HDR_VAR(8, s);
		assert(
				(incr >= 0 && sh->alloc - sh->len >= incr)
						|| (incr < 0 && sh->len >= (unsigned int )(-incr)));
		len = (sh->len += incr);
		break;
	}
	case SDS_TYPE_16:
	{
		SDS_HDR_VAR(16, s);
		assert(
				(incr >= 0 && sh->alloc - sh->len >= incr)
						|| (incr < 0 && sh->len >= (unsigned int )(-incr)));
		len = (sh->len += incr);
		break;
	}
	case SDS_TYPE_32:
	{
		SDS_HDR_VAR(32, s);
		assert(
				(incr >= 0 && sh->alloc - sh->len >= (unsigned int )incr)
						|| (incr < 0 && sh->len >= (unsigned int )(-incr)));
		len = (sh->len += incr);
		break;
	}
	case SDS_TYPE_64:
	{
		SDS_HDR_VAR(64, s);
		assert(
				(incr >= 0 && sh->alloc - sh->len >= (uint64_t )incr)
						|| (incr < 0 && sh->len >= (uint64_t )(-incr)));
		len = (sh->len += incr);
		break;
	}
	default:
		len = 0; /* Just to avoid compilation warnings. */
	}
	s[len] = '\0';
}

/* Grow the sds to have the specified length. Bytes that were not part of
 * the original length of the sds will be set to zero.
 *
 * if the specified length is smaller than the current length, no operation
 * is performed. */
sds sdsgrowzero(sds s, size_t len)
{
	size_t curlen = sdslen(s);

	if (len <= curlen)
		return s;
	s = sdsMakeRoomFor(s, len - curlen);
	if (s == NULL)
		return NULL;

	/* Make sure added region doesn't contain garbage */
	memset(s + curlen, 0, (len - curlen + 1)); /* also set trailing \0 byte */
	sdssetlen(s, len);
	return s;
}

/* Append the specified binary-safe string pointed by 't' of 'len' bytes to the
 * end of the specified sds string 's'.
 *
 * After the call, the passed sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscatlen(sds s, const void *t, size_t len)
{
	size_t curlen = sdslen(s);

	s = sdsMakeRoomFor(s, len);
	if (s == NULL)
		return NULL;
	memcpy(s + curlen, t, len);
	sdssetlen(s, curlen + len);
	s[curlen + len] = '\0';
	return s;
}

/* Append the specified null termianted C string to the sds string 's'.
 *
 * After the call, the passed sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscat(sds s, const char *t)
{
	return sdscatlen(s, t, strlen(t));
}

/* Append the specified sds 't' to the existing sds 's'.
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscatsds(sds s, const sds t)
{
	return sdscatlen(s, t, sdslen(t));
}

/* Destructively modify the sds string 's' to hold the specified binary
 * safe string pointed by 't' of length 'len' bytes. */
sds sdscpylen(sds s, const char *t, size_t len)
{
	if (sdsalloc(s) < len)
	{
		s = sdsMakeRoomFor(s, len - sdslen(s));
		if (s == NULL)
			return NULL;
	}
	memcpy(s, t, len);
	s[len] = '\0';
	sdssetlen(s, len);
	return s;
}

/* Like sdscpylen() but 't' must be a null-termined string so that the length
 * of the string is obtained with strlen(). */
sds sdscpy(sds s, const char *t)
{
	return sdscpylen(s, t, strlen(t));
}

/* Helper for sdscatlonglong() doing the actual number -> string
 * conversion. 's' must point to a string with room for at least
 * SDS_LLSTR_SIZE bytes.
 *
 * The function returns the length of the null-terminated string
 * representation stored at 's'. */
#define SDS_LLSTR_SIZE 21
int sdsll2str(char *s, long long value)
{
	char *p, aux;
	unsigned long long v;
	size_t l;

	/* Generate the string representation, this method produces
	 * an reversed string. */
	v = (value < 0) ? -value : value;
	p = s;
	do
	{
		*p++ = '0' + (v % 10);
		v /= 10;
	} while (v);
	if (value < 0)
		*p++ = '-';

	/* Compute length and add null term. */
	l = p - s;
	*p = '\0';

	/* Reverse the string. */
	p--;
	while (s < p)
	{
		aux = *s;
		*s = *p;
		*p = aux;
		s++;
		p--;
	}
	return l;
}

/* Identical sdsll2str(), but for unsigned long long type. */
int sdsull2str(char *s, unsigned long long v)
{
	char *p, aux;
	size_t l;

	/* Generate the string representation, this method produces
	 * an reversed string. */
	p = s;
	do
	{
		*p++ = '0' + (v % 10);
		v /= 10;
	} while (v);

	/* Compute length and add null term. */
	l = p - s;
	*p = '\0';

	/* Reverse the string. */
	p--;
	while (s < p)
	{
		aux = *s;
		*s = *p;
		*p = aux;
		s++;
		p--;
	}
	return l;
}

/* Create an sds string from a long long value. It is much faster than:
 *
 * sdscatprintf(sdsempty(),"%lld\n", value);
 */
sds sdsfromlonglong(long long value)
{
	char buf[SDS_LLSTR_SIZE];
	int len = sdsll2str(buf, value);

	return sdsnewlen(buf, len);
}

/* Like sdscatprintf() but gets va_list instead of being variadic. */
sds sdscatvprintf(sds s, const char *fmt, va_list ap)
{
	va_list cpy;
	char staticbuf[1024], *buf = staticbuf, *t;
	size_t buflen = strlen(fmt) * 2;

	/* We try to start using a static buffer for speed.
	 * If not possible we revert to heap allocation. */
	if (buflen > sizeof(staticbuf))
	{
		buf = s_malloc(buflen);
		if (buf == NULL)
			return NULL;
	} else
	{
		buflen = sizeof(staticbuf);
	}

	/* Try with buffers two times bigger every time we fail to
	 * fit the string in the current buffer size. */
	while (1)
	{
		buf[buflen - 2] = '\0';
		va_copy(cpy, ap);
		vsnprintf(buf, buflen, fmt, cpy);
		va_end(cpy);
		if (buf[buflen - 2] != '\0')
		{
			if (buf != staticbuf)
				s_free(buf);
			buflen *= 2;
			buf = s_malloc(buflen);
			if (buf == NULL)
				return NULL;
			continue;
		}
		break;
	}

	/* Finally concat the obtained string to the SDS string and return it. */
	t = sdscat(s, buf);
	if (buf != staticbuf)
		s_free(buf);
	return t;
}

/* Append to the sds string 's' a string obtained using printf-alike format
 * specifier.
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call.
 *
 * Example:
 *
 * s = sdsnew("Sum is: ");
 * s = sdscatprintf(s,"%d+%d = %d",a,b,a+b).
 *
 * Often you need to create a string from scratch with the printf-alike
 * format. When this is the need, just use sdsempty() as the target string:
 *
 * s = sdscatprintf(sdsempty(), "... your format ...", args);
 */
sds sdscatprintf(sds s, const char *fmt, ...)
{
	va_list ap;
	char *t;
	va_start(ap, fmt);
	t = sdscatvprintf(s, fmt, ap);
	va_end(ap);
	return t;
}

/* This function is similar to sdscatprintf, but much faster as it does
 * not rely on sprintf() family functions implemented by the libc that
 * are often very slow. Moreover directly handling the sds string as
 * new data is concatenated provides a performance improvement.
 *
 * However this function only handles an incompatible subset of printf-alike
 * format specifiers:
 *
 * %s - C String
 * %S - SDS string
 * %i - signed int
 * %I - 64 bit signed integer (long long, int64_t)
 * %u - unsigned int
 * %U - 64 bit unsigned integer (unsigned long long, uint64_t)
 * %% - Verbatim "%" character.
 */
sds sdscatfmt(sds s, char const *fmt, ...)
{
	const char *f = fmt;
	int i;
	va_list ap;

	va_start(ap, fmt);
	i = sdslen(s); /* Position of the next byte to write to dest str. */
	while (*f)
	{
		char next, *str;
		size_t l;
		long long num;
		unsigned long long unum;

		/* Make sure there is always space for at least 1 char. */
		if (sdsavail(s) == 0)
		{
			s = sdsMakeRoomFor(s, 1);
		}

		switch (*f)
		{
		case '%':
			next = *(f + 1);
			f++;
			switch (next)
			{
			case 's':
			case 'S':
				str = va_arg(ap, char*);
				l = (next == 's') ? strlen(str) : sdslen(str);
				if (sdsavail(s) < l)
				{
					s = sdsMakeRoomFor(s, l);
				}
				memcpy(s + i, str, l);
				sdsinclen(s, l);
				i += l;
				break;
			case 'i':
			case 'I':
				if (next == 'i')
					num = va_arg(ap, int);
				else
					num = va_arg(ap, long long);
				{
					char buf[SDS_LLSTR_SIZE];
					l = sdsll2str(buf, num);
					if (sdsavail(s) < l)
					{
						s = sdsMakeRoomFor(s, l);
					}
					memcpy(s + i, buf, l);
					sdsinclen(s, l);
					i += l;
				}
				break;
			case 'u':
			case 'U':
				if (next == 'u')
					unum = va_arg(ap, unsigned int);
				else
					unum = va_arg(ap, unsigned long long);
				{
					char buf[SDS_LLSTR_SIZE];
					l = sdsull2str(buf, unum);
					if (sdsavail(s) < l)
					{
						s = sdsMakeRoomFor(s, l);
					}
					memcpy(s + i, buf, l);
					sdsinclen(s, l);
					i += l;
				}
				break;
			default: /* Handle %% and generally %<unknown>. */
				s[i++] = next;
				sdsinclen(s, 1);
				break;
			}
			break;
		default:
			s[i++] = *f;
			sdsinclen(s, 1);
			break;
		}
		f++;
	}
	va_end(ap);

	/* Add null-term */
	s[i] = '\0';
	return s;
}

/* Remove the part of the string from left and from right composed just of
 * contiguous characters found in 'cset', that is a null terminted C string.
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call.
 *
 * Example:
 *
 * s = sdsnew("AA...AA.a.aa.aHelloWorld     :::");
 * s = sdstrim(s,"Aa. :");
 * printf("%s\n", s);
 *
 * Output will be just "Hello World".
 */
sds sdstrim(sds s, const char *cset)
{
	char *start, *end, *sp, *ep;
	size_t len;

	sp = start = s;
	ep = end = s + sdslen(s) - 1;
	while (sp <= end && strchr(cset, *sp))
		sp++;
	while (ep > sp && strchr(cset, *ep))
		ep--;
	len = (sp > ep) ? 0 : ((ep - sp) + 1);
	if (s != sp)
		memmove(s, sp, len);
	s[len] = '\0';
	sdssetlen(s, len);
	return s;
}

/* Turn the string into a smaller (or equal) string containing only the
 * substring specified by the 'start' and 'end' indexes.
 *
 * start and end can be negative, where -1 means the last character of the
 * string, -2 the penultimate character, and so forth.
 *
 * The interval is inclusive, so the start and end characters will be part
 * of the resulting string.
 *
 * The string is modified in-place.
 *
 * Example:
 *
 * s = sdsnew("Hello World");
 * sdsrange(s,1,-1); => "ello World"
 */
void sdsrange(sds s, int start, int end)
{
	size_t newlen, len = sdslen(s);

	if (len == 0)
		return;
	if (start < 0)
	{
		start = len + start;
		if (start < 0)
			start = 0;
	}
	if (end < 0)
	{
		end = len + end;
		if (end < 0)
			end = 0;
	}
	newlen = (start > end) ? 0 : (end - start) + 1;
	if (newlen != 0)
	{
		if (start >= (signed) len)
		{
			newlen = 0;
		} else if (end >= (signed) len)
		{
			end = len - 1;
			newlen = (start > end) ? 0 : (end - start) + 1;
		}
	} else
	{
		start = 0;
	}
	if (start && newlen)
		memmove(s, s + start, newlen);
	s[newlen] = 0;
	sdssetlen(s, newlen);
}

/* Apply tolower() to every character of the sds string 's'. */
void sdstolower(sds s)
{
	int len = sdslen(s), j;

	for (j = 0; j < len; j++)
		s[j] = tolower(s[j]);
}

/* Apply toupper() to every character of the sds string 's'. */
void sdstoupper(sds s)
{
	int len = sdslen(s), j;

	for (j = 0; j < len; j++)
		s[j] = toupper(s[j]);
}

/* Compare two sds strings s1 and s2 with memcmp().
 *
 * Return value:
 *
 *     positive if s1 > s2.
 *     negative if s1 < s2.
 *     0 if s1 and s2 are exactly the same binary string.
 *
 * If two strings share exactly the same prefix, but one of the two has
 * additional characters, the longer string is considered to be greater than
 * the smaller one. */
int sdscmp(const sds s1, const sds s2)
{
	size_t l1, l2, minlen;
	int cmp;

	l1 = sdslen(s1);
	l2 = sdslen(s2);
	minlen = (l1 < l2) ? l1 : l2;
	cmp = memcmp(s1, s2, minlen);
	if (cmp == 0)
		return l1 - l2;
	return cmp;
}

/* Split 's' with separator in 'sep'. An array
 * of sds strings is returned. *count will be set
 * by reference to the number of tokens returned.
 *
 * On out of memory, zero length string, zero length
 * separator, NULL is returned.
 *
 * Note that 'sep' is able to split a string using
 * a multi-character separator. For example
 * sdssplit("foo_-_bar","_-_"); will return two
 * elements "foo" and "bar".
 *
 * This version of the function is binary-safe but
 * requires length arguments. sdssplit() is just the
 * same function but for zero-terminated strings.
 */
sds *sdssplitlen(const char *s, int len, const char *sep, int seplen,
		int *count)
{
	int elements = 0, slots = 5, start = 0, j;
	sds *tokens;

	if (seplen < 1 || len < 0)
		return NULL;

	tokens = s_malloc(sizeof(sds) * slots);
	if (tokens == NULL)
		return NULL;

	if (len == 0)
	{
		*count = 0;
		return tokens;
	}
	for (j = 0; j < (len - (seplen - 1)); j++)
	{
		/* make sure there is room for the next element and the final one */
		if (slots < elements + 2)
		{
			sds *newtokens;

			slots *= 2;
			newtokens = s_realloc(tokens, sizeof(sds) * slots);
			if (newtokens == NULL)
				goto cleanup;
			tokens = newtokens;
		}
		/* search the separator */
		if ((seplen == 1 && *(s + j) == sep[0])
				|| (memcmp(s + j, sep, seplen) == 0))
		{
			tokens[elements] = sdsnewlen(s + start, j - start);
			if (tokens[elements] == NULL)
				goto cleanup;
			elements++;
			start = j + seplen;
			j = j + seplen - 1; /* skip the separator */
		}
	}
	/* Add the final element. We are sure there is room in the tokens array. */
	tokens[elements] = sdsnewlen(s + start, len - start);
	if (tokens[elements] == NULL)
		goto cleanup;
	elements++;
	*count = elements;
	return tokens;

	cleanup:
	{
		int i;
		for (i = 0; i < elements; i++)
			sdsfree(tokens[i]);
		s_free(tokens);
		*count = 0;
		return NULL;
	}
}

/* Free the result returned by sdssplitlen(), or do nothing if 'tokens' is NULL. */
void sdsfreesplitres(sds *tokens, int count)
{
	if (!tokens)
		return;
	while (count--)
		sdsfree(tokens[count]);
	s_free(tokens);
}

/* Append to the sds string "s" an escaped string representation where
 * all the non-printable characters (tested with isprint()) are turned into
 * escapes in the form "\n\r\a...." or "\x<hex-number>".
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscatrepr(sds s, const char *p, size_t len)
{
	s = sdscatlen(s, "\"", 1);
	while (len--)
	{
		switch (*p)
		{
		case '\\':
		case '"':
			s = sdscatprintf(s, "\\%c", *p);
			break;
		case '\n':
			s = sdscatlen(s, "\\n", 2);
			break;
		case '\r':
			s = sdscatlen(s, "\\r", 2);
			break;
		case '\t':
			s = sdscatlen(s, "\\t", 2);
			break;
		case '\a':
			s = sdscatlen(s, "\\a", 2);
			break;
		case '\b':
			s = sdscatlen(s, "\\b", 2);
			break;
		default:
			if (isprint(*p))
				s = sdscatprintf(s, "%c", *p);
			else
				s = sdscatprintf(s, "\\x%02x", (unsigned char) *p);
			break;
		}
		p++;
	}
	return sdscatlen(s, "\"", 1);
}

/* Helper function for sdssplitargs() that returns non zero if 'c'
 * is a valid hex digit. */
int is_hex_digit(char c)
{
	return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f')
			|| (c >= 'A' && c <= 'F');
}

/* Helper function for sdssplitargs() that converts a hex digit into an
 * integer from 0 to 15 */
int hex_digit_to_int(char c)
{
	switch (c)
	{
	case '0':
		return 0;
	case '1':
		return 1;
	case '2':
		return 2;
	case '3':
		return 3;
	case '4':
		return 4;
	case '5':
		return 5;
	case '6':
		return 6;
	case '7':
		return 7;
	case '8':
		return 8;
	case '9':
		return 9;
	case 'a':
	case 'A':
		return 10;
	case 'b':
	case 'B':
		return 11;
	case 'c':
	case 'C':
		return 12;
	case 'd':
	case 'D':
		return 13;
	case 'e':
	case 'E':
		return 14;
	case 'f':
	case 'F':
		return 15;
	default:
		return 0;
	}
}

/* Split a line into arguments, where every argument can be in the
 * following programming-language REPL-alike form:
 *
 * foo bar "newline are supported\n" and "\xff\x00otherstuff"
 *
 * The number of arguments is stored into *argc, and an array
 * of sds is returned.
 *
 * The caller should free the resulting array of sds strings with
 * sdsfreesplitres().
 *
 * Note that sdscatrepr() is able to convert back a string into
 * a quoted string in the same format sdssplitargs() is able to parse.
 *
 * The function returns the allocated tokens on success, even when the
 * input string is empty, or NULL if the input contains unbalanced
 * quotes or closed quotes followed by non space characters
 * as in: "foo"bar or "foo'
 */
sds *sdssplitargs(const char *line, int *argc)
{
	const char *p = line;
	char *current = NULL;
	char **vector = NULL;

	*argc = 0;
	while (1)
	{
		/* skip blanks */
		while (*p && isspace(*p))
			p++;
		if (*p)
		{
			/* get a token */
			int inq = 0; /* set to 1 if we are in "quotes" */
			int insq = 0; /* set to 1 if we are in 'single quotes' */
			int done = 0;

			if (current == NULL)
				current = sdsempty();
			while (!done)
			{
				if (inq)
				{
					if (*p == '\\' && *(p + 1) == 'x' && is_hex_digit(*(p + 2))
							&& is_hex_digit(*(p + 3)))
					{
						unsigned char byte;

						byte = (hex_digit_to_int(*(p + 2)) * 16)
								+ hex_digit_to_int(*(p + 3));
						current = sdscatlen(current, (char*) &byte, 1);
						p += 3;
					} else if (*p == '\\' && *(p + 1))
					{
						char c;

						p++;
						switch (*p)
						{
						case 'n':
							c = '\n';
							break;
						case 'r':
							c = '\r';
							break;
						case 't':
							c = '\t';
							break;
						case 'b':
							c = '\b';
							break;
						case 'a':
							c = '\a';
							break;
						default:
							c = *p;
							break;
						}
						current = sdscatlen(current, &c, 1);
					} else if (*p == '"')
					{
						/* closing quote must be followed by a space or
						 * nothing at all. */
						if (*(p + 1) && !isspace(*(p + 1)))
							goto err;
						done = 1;
					} else if (!*p)
					{
						/* unterminated quotes */
						goto err;
					} else
					{
						current = sdscatlen(current, p, 1);
					}
				} else if (insq)
				{
					if (*p == '\\' && *(p + 1) == '\'')
					{
						p++;
						current = sdscatlen(current, "'", 1);
					} else if (*p == '\'')
					{
						/* closing quote must be followed by a space or
						 * nothing at all. */
						if (*(p + 1) && !isspace(*(p + 1)))
							goto err;
						done = 1;
					} else if (!*p)
					{
						/* unterminated quotes */
						goto err;
					} else
					{
						current = sdscatlen(current, p, 1);
					}
				} else
				{
					switch (*p)
					{
					case ' ':
					case '\n':
					case '\r':
					case '\t':
					case '\0':
						done = 1;
						break;
					case '"':
						inq = 1;
						break;
					case '\'':
						insq = 1;
						break;
					default:
						current = sdscatlen(current, p, 1);
						break;
					}
				}
				if (*p)
					p++;
			}
			/* add the token to the vector */
			vector = s_realloc(vector, ((*argc) + 1) * sizeof(char*));
			vector[*argc] = current;
			(*argc)++;
			current = NULL;
		} else
		{
			/* Even on empty input string return something not NULL. */
			if (vector == NULL)
				vector = s_malloc(sizeof(void*));
			return vector;
		}
	}

	err: while ((*argc)--)
		sdsfree(vector[*argc]);
	s_free(vector);
	if (current)
		sdsfree(current);
	*argc = 0;
	return NULL;
}

/* Modify the string substituting all the occurrences of the set of
 * characters specified in the 'from' string to the corresponding character
 * in the 'to' array.
 *
 * For instance: sdsmapchars(mystring, "ho", "01", 2)
 * will have the effect of turning the string "hello" into "0ell1".
 *
 * The function returns the sds string pointer, that is always the same
 * as the input pointer since no resize is needed. */
sds sdsmapchars(sds s, const char *from, const char *to, size_t setlen)
{
	size_t j, i, l = sdslen(s);

	for (j = 0; j < l; j++)
	{
		for (i = 0; i < setlen; i++)
		{
			if (s[j] == from[i])
			{
				s[j] = to[i];
				break;
			}
		}
	}
	return s;
}

/* Join an array of C strings using the specified separator (also a C string).
 * Returns the result as an sds string. */
sds sdsjoin(char **argv, int argc, char *sep)
{
	sds join = sdsempty();
	int j;

	for (j = 0; j < argc; j++)
	{
		join = sdscat(join, argv[j]);
		if (j != argc - 1)
			join = sdscat(join, sep);
	}
	return join;
}

/* Like sdsjoin, but joins an array of SDS strings. */
sds sdsjoinsds(sds *argv, int argc, const char *sep, size_t seplen)
{
	sds join = sdsempty();
	int j;

	for (j = 0; j < argc; j++)
	{
		join = sdscatsds(join, argv[j]);
		if (j != argc - 1)
			join = sdscatlen(join, sep, seplen);
	}
	return join;
}

/* Wrappers to the allocators used by SDS. Note that SDS will actually
 * just use the macros defined into sdsalloc.h in order to avoid to pay
 * the overhead of function calls. Here we define these wrappers only for
 * the programs SDS is linked to, if they want to touch the SDS internals
 * even if they use a different allocator. */
void *sds_malloc(size_t size)
{
	return s_malloc(size);
}
void *sds_realloc(void *ptr, size_t size)
{
	return s_realloc(ptr, size);
}
void sds_free(void *ptr)
{
	s_free(ptr);
}

#if defined(SDS_TEST_MAIN)
#include <stdio.h>
#include "testhelp.h"
#include "limits.h"

#define UNUSED(x) (void)(x)
int sdsTest(void)
{
	{
		sds x = sdsnew("foo"), y;

		test_cond("Create a string and obtain the length",
				sdslen(x) == 3 && memcmp(x,"foo\0",4) == 0)

		sdsfree(x);
		x = sdsnewlen("foo",2);
		test_cond("Create a string with specified length",
				sdslen(x) == 2 && memcmp(x,"fo\0",3) == 0)

		x = sdscat(x,"bar");
		test_cond("Strings concatenation",
				sdslen(x) == 5 && memcmp(x,"fobar\0",6) == 0);

		x = sdscpy(x,"a");
		test_cond("sdscpy() against an originally longer string",
				sdslen(x) == 1 && memcmp(x,"a\0",2) == 0)

		x = sdscpy(x,"xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk");
		test_cond("sdscpy() against an originally shorter string",
				sdslen(x) == 33 &&
				memcmp(x,"xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk\0",33) == 0)

		sdsfree(x);
		x = sdscatprintf(sdsempty(),"%d",123);
		test_cond("sdscatprintf() seems working in the base case",
				sdslen(x) == 3 && memcmp(x,"123\0",4) == 0)

		sdsfree(x);
		x = sdsnew("--");
		x = sdscatfmt(x, "Hello %s World %I,%I--", "Hi!", LLONG_MIN,LLONG_MAX);
		test_cond("sdscatfmt() seems working in the base case",
				sdslen(x) == 60 &&
				memcmp(x,"--Hello Hi! World -9223372036854775808,"
						"9223372036854775807--",60) == 0)
		printf("[%s]\n",x);

		sdsfree(x);
		x = sdsnew("--");
		x = sdscatfmt(x, "%u,%U--", UINT_MAX, ULLONG_MAX);
		test_cond("sdscatfmt() seems working with unsigned numbers",
				sdslen(x) == 35 &&
				memcmp(x,"--4294967295,18446744073709551615--",35) == 0)

		sdsfree(x);
		x = sdsnew(" x ");
		sdstrim(x," x");
		test_cond("sdstrim() works when all chars match",
				sdslen(x) == 0)

		sdsfree(x);
		x = sdsnew(" x ");
		sdstrim(x," ");
		test_cond("sdstrim() works when a single char remains",
				sdslen(x) == 1 && x[0] == 'x')

		sdsfree(x);
		x = sdsnew("xxciaoyyy");
		sdstrim(x,"xy");
		test_cond("sdstrim() correctly trims characters",
				sdslen(x) == 4 && memcmp(x,"ciao\0",5) == 0)

		y = sdsdup(x);
		sdsrange(y,1,1);
		test_cond("sdsrange(...,1,1)",
				sdslen(y) == 1 && memcmp(y,"i\0",2) == 0)

		sdsfree(y);
		y = sdsdup(x);
		sdsrange(y,1,-1);
		test_cond("sdsrange(...,1,-1)",
				sdslen(y) == 3 && memcmp(y,"iao\0",4) == 0)

		sdsfree(y);
		y = sdsdup(x);
		sdsrange(y,-2,-1);
		test_cond("sdsrange(...,-2,-1)",
				sdslen(y) == 2 && memcmp(y,"ao\0",3) == 0)

		sdsfree(y);
		y = sdsdup(x);
		sdsrange(y,2,1);
		test_cond("sdsrange(...,2,1)",
				sdslen(y) == 0 && memcmp(y,"\0",1) == 0)

		sdsfree(y);
		y = sdsdup(x);
		sdsrange(y,1,100);
		test_cond("sdsrange(...,1,100)",
				sdslen(y) == 3 && memcmp(y,"iao\0",4) == 0)

		sdsfree(y);
		y = sdsdup(x);
		sdsrange(y,100,100);
		test_cond("sdsrange(...,100,100)",
				sdslen(y) == 0 && memcmp(y,"\0",1) == 0)

		sdsfree(y);
		sdsfree(x);
		x = sdsnew("foo");
		y = sdsnew("foa");
		test_cond("sdscmp(foo,foa)", sdscmp(x,y) > 0)

		sdsfree(y);
		sdsfree(x);
		x = sdsnew("bar");
		y = sdsnew("bar");
		test_cond("sdscmp(bar,bar)", sdscmp(x,y) == 0)

		sdsfree(y);
		sdsfree(x);
		x = sdsnew("aar");
		y = sdsnew("bar");
		test_cond("sdscmp(bar,bar)", sdscmp(x,y) < 0)

		sdsfree(y);
		sdsfree(x);
		x = sdsnewlen("\a\n\0foo\r",7);
		y = sdscatrepr(sdsempty(),x,sdslen(x));
		test_cond("sdscatrepr(...data...)",
				memcmp(y,"\"\\a\\n\\x00foo\\r\"",15) == 0)

		{
			unsigned int oldfree;
			char *p;
			int step = 10, j, i;

			sdsfree(x);
			sdsfree(y);
			x = sdsnew("0");
			test_cond("sdsnew() free/len buffers", sdslen(x) == 1 && sdsavail(x) == 0);

			/* Run the test a few times in order to hit the first two
			 * SDS header types. */
			for (i = 0; i < 10; i++)
			{
				int oldlen = sdslen(x);
				x = sdsMakeRoomFor(x,step);
				int type = x[-1]&SDS_TYPE_MASK;

				test_cond("sdsMakeRoomFor() len", sdslen(x) == oldlen);
				if (type != SDS_TYPE_5)
				{
					test_cond("sdsMakeRoomFor() free", sdsavail(x) >= step);
					oldfree = sdsavail(x);
				}
				p = x+oldlen;
				for (j = 0; j < step; j++)
				{
					p[j] = 'A'+j;
				}
				sdsIncrLen(x,step);
			}
			test_cond("sdsMakeRoomFor() content",
					memcmp("0ABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJ",x,101) == 0);
			test_cond("sdsMakeRoomFor() final length",sdslen(x)==101);

			sdsfree(x);
		}
	}
	test_report()
	return 0;
}
#endif

#ifdef SDS_TEST_MAIN
int main(void)
{
	return sdsTest();
}
#endif
